About Me

Tuesday, June 27, 2006

remember, tuesday is soylent green day

Problems are greater for other species, as Tim Flannery, a well-known Australian mammalogist and conservationist, makes clear in The Weather Makers. Ecosystems are based on interdependencies—between, for example, flower and pollinator, hunter and hunted, grazers and plant life—so the less mobile species have an impact on the survival of others. Of course climate fluctuated in the past, yet species adapted and flourished. But now the rate of climate change driven by human activity is reaching a level that dwarfs natural rates of change. And barriers created by human beings, such as urban sprawl and homogeneous agricultural fields, block many migration routes. If climate change is too great, natural barriers, such as coastlines, spell doom for some species.

Studies of more than one thousand species of plants, animals, and insects, including butterfly ranges charted by members of the public, found an average migration rate toward the North and South Poles of about four miles per decade in the second half of the twentieth century. That is not fast enough. During the past thirty years the lines marking the regions in which a given average temperature prevails ("isotherms") have been moving poleward at a rate of about thirty-five miles per decade. That is the size of a county in Iowa. Each decade the range of a given species is moving one row of counties northward.

[snip]

In the Earth's history, during periods when average global temperatures increased by as much as ten degrees Fahrenheit, there have been several "mass extinctions," when between 50 and 90 percent of the species on Earth disappeared forever. In each case, life survived and new species developed over hundreds of thousands of years. The most recent of these mass extinctions defines the boundary, 55 million years ago, between the Paleocene and Eocene epochs. The evolutionary turmoil associated with that climate change gave rise to a host of modern mammals, from rodents to primates, which appear in fossil records for the first time in the early Eocene.

[snip]

The greatest threat of climate change for human beings, I believe, lies in the potential destabilization of the massive ice sheets in Greenland and Antarctica. As with the extinction of species, the disintegration of ice sheets is irreversible for practical purposes. Our children, grandchildren, and many more generations will bear the consequences of choices that we make in the next few years.

The level of the sea throughout the globe is a reflection primarily of changes in the volume of ice sheets and thus of changes of global temperature. When the planet cools, ice sheets grow on continents and the sea level falls. Conversely, when the Earth warms, ice melts and the sea level rises. In Field Notes from a Catastrophe, Elizabeth Kolbert reports on the work of researchers trying to understand the acceleration of melting, and in his new book and film An Inconvenient Truth, Al Gore graphically illustrates possible effects of a rising sea level on Florida and other locations.

Ice sheets waxed and waned as the Earth cooled and warmed over the past 500,000 years. During the coldest ice ages, the Earth's average temperature was about ten degrees Fahrenheit colder than today. So much water was locked in the largest ice sheet, more than a mile thick and covering most of Canada and northern parts of the United States, that the sea level was 400 feet lower than today. The warmest interglacial periods were about two degrees Fahrenheit warmer than today and the sea level was as much as sixteen feet higher.

[snip]

The business-as-usual scenario yields an increase of about five degrees Fahrenheit of global warming during this century, while the alternative scenario yields an increase of less than two degrees Fahrenheit during the same period. Warming can be predicted accurately based on knowledge of how Earth responded to similar levels of greenhouse gases in the past. (By drilling into glaciers to analyze air bubbles trapped under layers of snow, scientists can measure the levels of each gas in the atmosphere hundreds of thousands of years ago. By comparing the concentrations of different isotopes of oxygen in these air bubbles, they can measure the average temperature of past centuries.) Climate models by themselves yield similar answers. However, the evidence from the Earth's history provides a more precise and sensitive measure, and we know that the real world accurately included the effects of all feedback processes, such as changes of clouds and water vapor, that have an effect on temperature.

[snip]

Why are the same scientists and political forces that succeeded in controlling the threat to the ozone layer now failing miserably to deal with the global warming crisis? Though we depend on fossil fuels far more than we ever did on CFCs, there is plenty of blame to go around. Scientists present the facts about climate change clinically, failing to stress that business-as-usual will transform the planet. The press and television, despite an overwhelming scientific consensus concerning global warming, give equal time to fringe "contrarians" supported by the fossil fuel industry. Special interest groups mount effective disinformation campaigns to sow doubt about the reality of global warming. The government appears to be strongly influenced by special interests, or otherwise confused and distracted, and it has failed to provide leadership. The public is understandably confused or uninterested.

I used to spread the blame uniformly until, when I was about to appear on public television, the producer informed me that the program "must" also include a "contrarian" who would take issue with claims of global warming. Presenting such a view, he told me, was a common practice in commercial television as well as radio and newspapers. Supporters of public TV or advertisers, with their own special interests, require "balance" as a price for their continued financial support. Gore's book reveals that while more than half of the recent newspaper articles on climate change have given equal weight to such contrarian views, virtually none of the scientific articles in peer-reviewed journals have questioned the consensus that emissions from human activities cause global warming. As a result, even when the scientific evidence is clear, technical nit-picking by contrarians leaves the public with the false impression that there is still great scientific uncertainty about the reality and causes of climate change.

The executive and legislative branches of the US government seek excuses to justify their inaction. The President, despite conclusive reports from the Intergovernmental Panel on Climate Change and the National Academy of Sciences, welcomes contrary advice from Michael Crichton, a science fiction writer. Senator James Inhofe, chairman of the Committee on Environment and Public Works, describes global warming as "the greatest hoax ever perpetrated on the American people" and has used aggressive tactics, including a lawsuit to suppress a federally funded report on climate change, to threaten and intimidate scientists.

Policies favoring the short-term profits of energy companies and other special interests are cast by many politicians as being in the best economic interests of the country. They take no account of the mounting costs of environmental damage and of the future costs of maintaining the supply of fossil fuels. Leaders with a long-term vision would place greater value on developing more efficient energy technology and sources of clean energy. Rather than subsidizing fossil fuels, the government should provide incentives for fossil-fuel companies to develop other kinds of energy.

Who will pay for the tragic effects of a warming climate? Not the political leaders and business executives I have mentioned. If we pass the crucial point and tragedies caused by climate change begin to unfold, history will judge harshly the scientists, reporters, special interests, and politicians who failed to protect the planet. But our children will pay the consequences.